dotnet / dotnet/perf-autofiling-issues

[Perf] Linux/x64: 13 Regressions on 8/24/2026 1:18:54 AM +00:00

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arch-wasm arch-x64 branch-refs/heads/main compilationmode-wasm kind-micro Look Again os-linux perf-regression runkind-micro untriaged
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Description

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [efc7248c8c8a7aa7ad30a58623ee5284ce462a17](https://github.com/dotnet/runtime/commit/efc7248c8c8a7aa7ad30a58623ee5284ce462a17)
Compare | [d5d5cbcba8af2882afdda08e5b667206c7dbf09a](https://github.com/dotnet/runtime/commit/d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/efc7248c8c8a7aa7ad30a58623ee5284ce462a17...d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Memory.Span<Byte>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 46.00 ns | 75.08 ns | 1.63 | 0.13 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 47.00 ns | 75.54 ns | 1.61 | 0.13 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 92.85 ns | 118.41 ns | 1.28 | 0.06 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 449.11 ns | 481.97 ns | 1.07 | 0.02 | False | | |

![graph]()
![graph]()
![graph]()
![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Byte>.ToArray(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Byte>.ToArray(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Byte>.ToArray(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Byte>.ToArray(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [efc7248c8c8a7aa7ad30a58623ee5284ce462a17](https://github.com/dotnet/runtime/commit/efc7248c8c8a7aa7ad30a58623ee5284ce462a17)
Compare | [d5d5cbcba8af2882afdda08e5b667206c7dbf09a](https://github.com/dotnet/runtime/commit/d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/efc7248c8c8a7aa7ad30a58623ee5284ce462a17...d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Memory.Span<Char>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 47.17 ns | 74.97 ns | 1.59 | 0.18 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 51.53 ns | 78.50 ns | 1.52 | 0.16 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 129.74 ns | 156.65 ns | 1.21 | 0.08 | False | | |

![graph]()
![graph]()
![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Char>.ToArray(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.ToArray(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.ToArray(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [efc7248c8c8a7aa7ad30a58623ee5284ce462a17](https://github.com/dotnet/runtime/commit/efc7248c8c8a7aa7ad30a58623ee5284ce462a17)
Compare | [d5d5cbcba8af2882afdda08e5b667206c7dbf09a](https://github.com/dotnet/runtime/commit/d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/efc7248c8c8a7aa7ad30a58623ee5284ce462a17...d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Memory.Span<Int32>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 38.73 ns | 74.68 ns | 1.93 | 0.12 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 56.34 ns | 88.72 ns | 1.57 | 0.11 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 187.01 ns | 215.83 ns | 1.15 | 0.05 | False | | |

![graph]()
![graph]()
![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Int32>.ToArray(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.ToArray(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.ToArray(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [efc7248c8c8a7aa7ad30a58623ee5284ce462a17](https://github.com/dotnet/runtime/commit/efc7248c8c8a7aa7ad30a58623ee5284ce462a17)
Compare | [d5d5cbcba8af2882afdda08e5b667206c7dbf09a](https://github.com/dotnet/runtime/commit/d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/efc7248c8c8a7aa7ad30a58623ee5284ce462a17...d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Perf_Convert

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

  • [FromBase64String - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 245.17 ns | 269.51 ns | 1.10 | 0.18 | False | | |

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Perf_Convert*'
```

### System.Perf_Convert.FromBase64String

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [efc7248c8c8a7aa7ad30a58623ee5284ce462a17](https://github.com/dotnet/runtime/commit/efc7248c8c8a7aa7ad30a58623ee5284ce462a17)
Compare | [d5d5cbcba8af2882afdda08e5b667206c7dbf09a](https://github.com/dotnet/runtime/commit/d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/efc7248c8c8a7aa7ad30a58623ee5284ce462a17...d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Memory.Memory<Byte>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 102.02 ns | 116.78 ns | 1.14 | 0.05 | False | | |

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Memory*'
```

### System.Memory.Memory<Byte>.ToArray(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [efc7248c8c8a7aa7ad30a58623ee5284ce462a17](https://github.com/dotnet/runtime/commit/efc7248c8c8a7aa7ad30a58623ee5284ce462a17)
Compare | [d5d5cbcba8af2882afdda08e5b667206c7dbf09a](https://github.com/dotnet/runtime/commit/d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/efc7248c8c8a7aa7ad30a58623ee5284ce462a17...d5d5cbcba8af2882afdda08e5b667206c7dbf09a)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Memory.Memory<Char>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 142.69 ns | 156.59 ns | 1.10 | 0.35 | False | | |

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Memory*'
```

### System.Memory.Memory<Char>.ToArray(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with src/benchmarks/micro/libraries/System.Memory/Span.cs at lines 59-60 and compare the linked baseline and test reports for the ToArray benchmarks. Run the provided benchmarks_ci.py command with the System.Memory.Span* filter, then investigate the reported wasm regression across the listed sizes. Done means the regression is addressed and the benchmark results are rerun to verify the change.

Written by the indexing model from the issue text.

Assessment

Tech stack
python, wasm
Domain
performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
45/100

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